A typical vehicle occupant restraint system includes a gas bag transposable from a space-saving, folded resting condition into a deployed condition.
When necessary, the gas bag is transposed by means of an inflator from the folded resting condition into the deployed condition in which it restrains a vehicle occupant as specified. In the deployed condition the shape of the gas bag as well as its position in the vehicle interior relative to the vehicle occupant is usually dictated by the position, number and length of the catch straps arranged in the interior of the gas bag.
Because of the velocity with which the gas bag needs to be deployed so that it attains its optimum position in due time to cushion the vehicle occupant, injuries may occur if the wall of the gas bag during deployment impinges part of the body of the vehicle occupant. This problem is aggravated more particularly when the vehicle occupant happens to be not in his usual position at the point in time of activation of the gas bag, it being in this usual position that he has a predetermined minimum spacing away from the gas bag. Namely, the closer the vehicle occupant is located to the folded gas bag, the greater the likelihood of being hit by wall parts of the gas bag before the gas bag has attained its fully deployed condition, and the greater the energy of the wall parts with which the vehicle occupant comes into contact. Another problem in this respect is that one and the same gas bag needs to restrain vehicle occupants differing in constitution, i.e. to reliably restrain, for example, a heavy male vehicle occupant the gas bag needs to be designed substantially more voluminous than in the case of restraining for example a lighter female vehicle occupant. Accordingly, it is sometimes the case that the gas bag is deployed with unnecessarily high energy which increases the risk of injury.
The object of the invention is to provide a vehicle occupant restraint system including a gas bag posing as small a risk of injury as possible even in the case of an unfavorable vehicle occupant constitution or seating position.